Fig. 2.

Sensitivity enhancement based on sample enrichment. A Paper-based ICP pre-concentrators integrated with LFA for β-hCG detection [71]. B Experimental setup for (a) ITP-enhanced LFA and (b) conventional LFA. (c) Experimental snapshots were taken at 5 different time points [72]. C The 3-D paper is well combined with ATPS and LFA for transferrin detection [73]. (a) The 3-D paper well device was combined with a transferrin competition assay on nitrocellulose paper. Samples containing no transferrin were correctly diagnosed when using the (b) 1:1 or (c) 9:1 volume ratio of ATPS solutions. D Schematic of the integrated device of the semi-permeable membrane, glass fiber, and PEG buffer into with LFA [74]